The present invention relates to a method and apparatus for locating and loosening a reserve yarn winding on a textile spinning cop or a like textile yarn bobbin of the type wherein the reserve yarn winding is wound with a relatively large rise in the direction from the nose end of the cop to the foot end of the cop.
In ring spinning machines and the like, it is customary at the completion of the formation of a yarn cop to form a reserve winding of the terminal length of the yarn to extend from the upper end, or nose, of the cop to the lower end, or foot, of the cop. For this purpose, for example, the ring rail in a ring spinning machine is moved at a relatively rapid rate from the upper nose end of the cops being wound downwardly therealong while the spindles on which the cops are supported are in the process of decelerating. The reserve yarn winding may then be terminated at the foot end of the cop in an underwinding.
Typically, such a reserve yarn winding is formed in only a few wraps of the yarn about the cop. For example, approximately five yarn windings are normally located on the upper conical portion of the yarn buildup of the cop with approximately five to six windings formed on the cylindrical portion of the yarn-buildup on the cop.
When such cops are prepared for unwinding, it is necessary and important to expose the terminal yarn end of the reserve yarn winding without damaging the reserve yarn winding, so that the terminal yarn end may be easily grasped, such as by a winding device with reliability.
A reserve winding of yarn which lies firmly on the outer periphery of the yarn buildup of the cop is advantageous in facilitating the transportation of the cop from the spinning machine to a subsequent winding machine in that the reserve yarn winding is less likely to catch on other objects and be torn from the cop or to become entangled with the reserve yarn windings of other cops. On the other hand, the reserve yarn winding will remain firmly adhered to the cop at the yarn delivery position of an automatic winder. It is accordingly advantageous to locate and loosen the reserve yarn winding in advance of a subsequent unwinding operation, such as at an automatic winder, or even before the cop is inserted at the winding position. This procedure is commonly referred to as cop preparation and is preferably performed in the immediate vicinity of an automatic winder or like winding machine.
In the course of a cop preparation procedure, the reserve yarn winding can be exposed and placed at a defined position with respect to the cop. For example, it is customary to shorten the terminal end of the reserve yarn winding to a predetermined length and to insert the yarn end into the interior of the tubular core of the cop, either before or after the shortening takes place, so that the yarn end loops around the terminal end edge of the tube so as to be positioned to be reliably grasped when the cop is placed in a winding position at the winding machine.
Problems have been experienced in locating and loosening the reserve yarn winding utilizing conventional suction, blowing, scratching and catching devices for this purpose which, in practice, have not been found to perform with satisfactory reliability.